This section provides background information related to the present disclosure which is not necessarily prior art.
Vehicles such as snowmobiles utilize two stroke engines which are run at high RPM. These two stroke engines produce a significant amount of heat which builds up in engine components reducing component life expectancy. Traditionally, this heat needs to be removed from the engine using fluid cooling systems that circulate cooling fluid through the engine block and head of the engine to remove heat. Unfortunately, at high RPM, resonances in the engine's exhaust system causes heated exhaust gas, which often contains unburned fuel, to impinge on the sides and skirt of the piston.
Further, inherent in the nature of the fuel to air mixtures for two cycle engines, it is often not possible to entirely burn all of the fuel in a combustion cycle. Often this unburned fuel arises from imperfect fluid dynamics with a cylinder. Eventually, upon exhaustion of the combustion gasses, this unburned fuel is sent into the exhaust system which may be lead to secondary combustion or emissions problems. Further, piston down stroke, gasses from the exhaust port are often pulled back into the combustion chamber to help mix new fuel and air as well as enhance the fuel to air concentration by augmenting the new fuel with unburned fuel from a previous engine cycle.
There is a need to improve exhaust and fuel mixing within a two cycle engine to reduce emissions, heat problems, and improve engine longevity. It is therefore an intention of the present teachings to improve engine performance with these goals in mind.